PEPTIDERGIC INNERVATION OF THE INTERNAL ANAL-SPHINCTER IN HIRSCHSPRUNGS-DISEASE

The pathophysiology of the impaired sphincter function in Hirschsprung 's disease is still unclear. The peptidergic innervation of the agangl ionic large intestine is known to be disturbed. The present study anal yzes the peptidergic innervation of the aganglionic internal anal sphi ncter (IAS) in comparison with that of the circular layer of ganglioni c and aganglionic large intestine. Immunoreactivity for the following substances was analyzed: vasoactive intestinal polypeptide (VIP), subs tance P (SP), met-enkephalin (ENK), calcitonin gene-related peptide (C GRP), somatostatin (SOM), and neuropeptide Y (NPY). All patients were operated upon with Soave's endorectal pull-through technique and a pos terior partial myectomy of the IAS. For comparison, specimens of resec ted IAS from adult patients operated upon for rectal cancer as well as autopsy specimens from a 2-year-old child were analyzed. Differences in the density of nerve fibers between the ganglionic and aganglionic large intestine were in accordance with previous studies. In sections of normoganglionic IAS moderately dense networks of nerve fibers immun oreactive for NPY, SOM, and VIP were observed. The occurrence of NPY a nd SOM was somewhat more frequent here compared to the colonic circula r muscle coat, whereas the opposite was seen for VIP. In aganglionic I AS abundant nerve fibers immunoreactive for NPY, SOM, and VIP were obs erved. Only a few SP-, CGRP-, and ENK-immunoreactive fibers were found in normal and aganglionic IAS. It is concluded that there were modera te differences in the peptidergic innervation of the aganglionic IAS a s compared to the normal ganglionic IAS and the circular muscle coat o f the ganglionic and aganglionic large intestine.